Process of reducing zinc compounds.



i. B." GUTTER PROCESS 0F RBDUCING ZINC COMPOUNDS. `APPLICAIION FILED' SEPT. 15, 1913.

1,080,102; t --IPatent'ed Dec.2, 1913.

. fromr the i solution in a UNITED s'rArEs rA'rENr orrrc,

ELIsHA ,n CUTTEN, or ERIE, PENNSYLVANIA.

PROCESS 0F REDUCING ZINC COMPOUNDS.

to the expenses for fuel and repairs and thev losses due to the breakage of retorts which rapidly deteriorate in use, especially when working on ores containing lead and iron, have led to frequent proposals to smelt zinc oresin cupola furnaces. All such attempts as have belen made I believeto have been unsuccessful, because the vapor of metallic zincv has been reoxidized before it could be collected; and because the fluxing material necessarily present preventsprecipitation of the zinc.

According to my process I' employ zinc oxid free from gangueand other bodies as the snbstanceto be reduced, and effect its reduction in a cupola or low blast furnace in a reducing atmosphere `under pressure, collecting and drawing off the liquid zinc from beneath the charge. v

The' zinc oxid for the charge, free. from anuue and com ounds of other metals ma g e: p a

be obtained in any desired way. Forinstance a substantially pure zinc oxid may be obtained asA follows: Thoroughly roasted, (oxidized) sultid ore or a carbonate ore containing zinc is treated with a cold, dilute solution o-f an acid, s uch as sulfuric or hydrochloric acid, and the mixture allowed to stand until cold, then; if the quantity of acid be properly proportioned to the contained zinc the solution* on beingv drawn o if will be found to be substantially free from ther sulfates; and if' there be traces 4of other'I metals they may be removed in any suitable way lr-nown to those skilled in ,the ant. This solution ofzinc sulfate may-then be treated with ammonia which will precipitate zinc hydrated oxid that filter press. hydrated oxid is then preferably dried and Specification of Letters Patent. Application mea september 15, 1913. serial No. 789,843.

in the county of `Erie and State of Pennsylvania, have invented a Patented Dec. 2, 1913.

objectionable traces of iron or other metals be present they may be removed in any well known way. Any other preferred method of obtaining zinc oxid may be employed. The

coke or coal, and preferably briqueted in any well known way. The briquets, however, should not contain any material quantity of slag forming, or other inert matter, as they would if clay were used as a binder. kThis mixture of zinc oxid and coke or coal stitutes the charge of any ,form of Vfurnace capable of withstanding internal pressure.

gaseous fuel with air, both under high presgases of combustion contained in the furnace raised may be separated- This (QU) to sixty (GO) pounds to the square inch, or' even higher, and this pressure should be maintained throughout the reduction operation. rfhe object of this high pressure is to use of liquid or gaseous fuel may be'omitted, air only under proper pressure' being. introduced at the twy'ers, andthe carbon mixed with the zinc oxidA and in combustion being `depended upon both for the heat requisite for the operation as well as for the chemical reaction, '27. e., the combustion of the oxygen 'with the carbon` which passes off as carbon `monoxid. If fluid fuel with air be forced in at the bottom of the charge, as will be preferably done, it will be found advantageous to force them in quantities so proportioned as to produce a reducing flame at that point. By this procedure the possibility of having oxidizing); gases within the furnace chamber, as might be the case if a neutral flame were employed at this point` is prevented,since if any carbonic oxid (CO2) were formed by the reduction of the zinc"oxid, it would itself be reduced by the carbon of the charge into carbon monoxid (CO) before it had an opportunity of reoxidizing any of the reducedv Zinc.A It is "thought, however, that with a flame of that character no format-ion of carbonic oxid (CO2) could oecur. -Operating in this way, it will be found t atthe .zinc oxid will be reducedand that etallip zinc in a liquid form will collect beneath the furnace charge-and may be drawn off at the termination of the process or preferably, from time to time.

zinc oxid, however, obtained, is mixed with Thefurnace having been charged, liquid or Y prevent vapcrizing the metalliczinc.` Thev heated to form the'oxid before use. Should Y.

sure, are admitted to the ,bot-tom' 'of the charge and ignited; and the pressure of the as soon as possible to from twenty llO ' The furnace is formed 4the necessary strength In the accompanying drawing I showin sectional elevation a form offurnace which may be employed in the process.

A is a charging chamber, beneathv which is the reducing chamber B of the furnace. of an iron vcasing of lined with fire brick. At or near the bottom of the reducing chamber is located the blast and fuel channel with which communicatethe usual blast or fuel pipes and at another point a tap hole D. E communicates with the upper portion of the reducing chamber and is provided with a Weighted valve adjusted to maintain the desired pressurein the furnace. The charging chamber is provided with a Water cooled bell seat G in its bottom anda cover H on its top provided with any securing means. The bell I is provided With a stem movable through the cover H and screw threaded at its upper end to receive the hand nut K, resting on standard L.

In starting or blowin in the above described furnace it might e Well to start the blast and obtain the pressurein the reducing chamber, before charging, but if there should be any reoxidation of zinc then, or at any time, from failure to maintain the prescribed conditions, it would do no harm as thereduction would be subsequently efj fected' when the proper conditions Were established. It Will generally be found that the required pressure is obtained at the start before the reducing temperature is reached.

While -I have heretofore referred only to and preferably vused as the reducible zinc compound, the oXid, other reducible zinc compounds such as the sulfate or carbonate may be used.

The process herein described is radically distinguished from those heretofore pro- 'posed in-Which it has been suggested that refractory zinc ore be charged with fluxing material in acupola furnace. Such a process is not capable of practical operation for reasons Weli `understood. In my process no uxing material is required and if used would be present as mere inert matter detri mental to the operation and impairing its efficiency.

I claim:

1. The process of reducing zinc com pounds free from slag forming materials which consists in subjecting them in the absence of fluXing material but in the presence of carbon to a temperature ordinarily suffi-y cient to vaporize metallic zinc, and under a pressure sufficiently highy to prevent such vaporization, the zinc being thereby precipitated asv molten metallic zinc, substantially as set forth.

2. The process of reducing zinc compounds free from slag forming materials which consists in subjecting them to reduc-- 'ing gases under pressure and at a reducing temperature and to a solid reducing agent, substantially as described. l

3. The process of reducing zinc oXid free from slag forming materials which consists in subjecting it in presence of carbon v to a high temperature and high presse-rgi'l substantially as described.-

4. The process of reducing zinc oxid free from slag forming materials which consists in subjecting it to reducing gases under pressure at a reducing temperature and to a'solid reducing agent substantially as de scribed.

, In testimony whereof,l I have hereunto subscribed my name. Y ELISIIA B. CUTTEN.

Witnesses:

LLOYD B. Wienr,

A. N. MrroHnLL. 

